This invention relates to a pharmaceutical composition which comprises a peptide capable of inhibiting the interaction between immunoglobulins and their receptors.
It is known that the interaction between immunoglobulins (Igs) and their related receptors placed on the cellular surface, induces a series of different reactions depending on the ig isotype recognized by the receptor. For example, the binding on macrophages of immunoglobulins G to their related receptors FcgR leads to endocytosys, to complex antigen antibody lysosomal degradation and to secretion of potent inflammation mediators like prostaglandins, leukotriens, oxygen intermediates and neutral proteases (Unkeless et al., 1981, J.Exp.Med.171, 597-611).
Is also known that immunoglobulins interact with their related receptors by the constant portion, named Fc, independently of the antibody antigen specificity (Fridman et al., 1992, Immunol. Rev. 125, 49-76).
Synthetic compounds capable of interfering with the immunoglobulin/receptor interaction are not yet available. Only the soluble forms of the natural receptors, named sFcR, obtained as recombinant products, through genetic engineering techniques, are actually capable to act as inhibitors of this important interaction (Sautes et al., 1994, J. Chrom. 662, 197-207).
It is therefore apparent that the inhibition of the interaction between immunoglobulins and receptors is an important therapeutic approach in all those cases where it is important to control the effects of an Ig over-production and when the effects generated by the Ig/receptor recognition are negative for the cell cycle.
For example, in the multiple myeloma, an incurable tumor disease since it is resistant to standard chemotherapy, experimental data have indicated that a flanking immunotherapy based on the administration of soluble receptors for Fc reduces tumor cells growing and immunoglobulins secretion (Hoover et al., J. Clin. Invest. 95, 241-247).
In turn, in acquired immunodeficiency (AIDS), in patients sera are present antibodies that increase virus infectivity interacting with the respective cellular receptors (Homsy et al., 1989, Science 244, 1357-1360) and consequently, a therapy based on the administration of molecules capable of interfering with receptors that interact with Igs is of remarkable therapeutic importance for HIV virus infectivity.
Also in diseases of inflammatory origin, as the rheumatoid arthritis, the event that leads to the pathologic condition is the immunoglobulins interaction with the corresponding cellular receptors (Fearon and Wong, 1983, Ann. Rev. Immunol. 1, 243) and, as in the previous cases, a treatment based on the administration of molecules capable of interfering with the recognition Ig/receptor can give notable therapeutic benefits.
Even allergic reactions are triggered by the interaction of immunoglobulins, in this case of the E class, with the corresponding cellular receptors.
Given the wide therapeutic application spectrum and the pathology sternness there is therefore a great demand of synthetic compounds, and therefore free of contaminants of biological origin and of low cost, that could be capable of interfering with the interaction between immunoglobulins and the related receptors.
Now it has been found that these properties are owned by a peptide of formula (I):
(AA1-Thr-AA2-)n-Rxe2x80x83xe2x80x83(I)
wherein
AA1 and AA2 different one another, are an amino acidic residue of tyrosine and arginine, in the L or D configuration, wherein the hydroxy group of threonine and the guanidine moiety of arginine may be protected by a compound conventionally used in peptide chemistry for protecting the hydroxy group and the guanidine moiety, respectively,
n is 2,3,or 4, and
R is a group capable of forming a dimeric, trimeric, and respectively tetrameric peptide.
The preparation of these compounds has been described in the european patent application n. 96201706.7 of 19.06.1996 in the name of the same applicant. Said application, not yet published, describes the properties of the compounds as immunoglobulins ligands.
Therefore, it is a first object of this invention to provide a pharmaceutical composition comprising a biologically effective amount of a peptide of formula (I):
(AA1-Thr-AA2-)n-Rxe2x80x83xe2x80x83(I)
wherein AA1 and AA2, different from one another, are an amino acid residue of
tyrosine and arginine, in L or D configuration, wherein the hydroxy group of threonine and the guanidine moietly of arginine may be protected by a compound conventionally used in peptide chemistry for protecting the hydroxy group and the guanidine moiety, respectively,
n is 2, 3, or 4.
R is a group capable to form a dimeric, trimeric, and respectively tetrameric peptide,
and at least a pharmaceutically acceptable inert ingredient.
Preferably n is 4.
Each amino acid of the compound of formula (I) can have L or D configuration.
In the present description and in the claims, the terms xe2x80x9cdimerxe2x80x9d xe2x80x9ctrimerxe2x80x9d and xe2x80x9ctetramerxe2x80x9d intend to mean peptides comprising two, three and respectively four sequences AA1-Thr-AA2- where AA1 and AA2 have the above mentioned meanings.
A typical example of a suitable group for forming a dimer (n=2) is a lysine residue. A typical example of a suitable group for forming a trimer (n=3) is a dipeptide lysine-lysine of formula Lys-Lys. Typical examples of suitable groups for forming a tetramer (n=4) are a branched tripeptide of formula Lys-Lys(xcex52Lys) and a branched tetrapeptide of formula Gly-Lys-Lys(xcex5Lys).
A typical example of a tetramer of formula (I) has the following formula
(AA1-Thr-AA2-)4-(Lys)2-Gly-OHxe2x80x83xe2x80x83(IA)
wherein
AA1 and AA2 have the above mentioned meanings, and wherein the hydroxy group of threonine and tyrosine and the guanidine moiety of arginine may be protected by a compound conventionally used in peptide chemistry for protecting the hydroxy group and the guanidine moiety, respectively.
Many group useful for protecting the hydroxy group are reported in the literature (Grant G. A. xe2x80x9cSynthetic peptides: a users guidexe2x80x9d Freeman, N.Y., 1992).
Typical examples of said protecting groups are the ter-butyl (tBu) (La Joie G., Crivici A., Adamson J. G., xe2x80x9cSynthesysxe2x80x9d 571-572 (1990) and the benzyl group (Yojima xe2x80x9cTetrahedronxe2x80x9d 44: 805-819 (1988)).
Many groups useful for protecting the guanidine moiety of arginine are also known from the literature (Grant G. A. xe2x80x9cSynthetic peptides: a user""s guidexe2x80x9d Freeman, N.Y., 1992).
Typical examples of said protecting group are: 2,2,5,7,8-pen-tamethylcroman-6-sulphonyl (Pmc) and 4-methoxy-2,3,6-trimethylbenzene (Mtr) (Ramage and Green xe2x80x9cTetrahedron Lettersxe2x80x9d, 28, 2287 (1987); Fujiino et al. xe2x80x9cChem. Pharm. Bull., 29, 2825, (1981).
Specific examples of compound of formula (IA) are
(H2N-L-Arg(Pmc)-L-Thr(OtBu)-L-Tyr(OtBU)-CO)4-(Lys)2-Lys-Gly-OHxe2x80x83xe2x80x83(P-PAM)
(H2N-L-Arg-L-Thr-L-Tyr-CO)4-(Lys)2-Lys-Gly-OHxe2x80x83xe2x80x83(L-PAM)
(H2N-D-Arg-D-Thr-D-Tyr-CO)4-(Lys)2-Lys-Gly-OHxe2x80x83xe2x80x83(D-PAM)
As described in detail below, the biological activity of formula (I) peptides has been assayed in the inhibition of the binding between immunoglobulin and receptor (Ig-FcR) and in the rosettes formation inhibition between sheep red blood cells (SRBC) derivatized with human IgG and U937 cells and the result was that compounds of formula (I) produce on Ig receptor the same interaction as Ig and that said interaction is dose-dependent. In addition, the biological activity of the compounds of formula (I) has been evaluated in vivo by passive cutaneous anaphylaxis assay, which represents the animal model for the study of antiallergic compounds.
In mouse acute toxicity tests the compounds of formula (I) are well tolerated either by oral or by intravenous administration.
Typical examples of pathologic conditions that may benefit from the treatment with a pharmaceutical composition according to this invention are those where it is useful or necessary to interfere on the interaction between Ig and their receptors. Typical examples of these pathological conditions are rheumatoid arthritis, and allergic reactions.
Preferably, the pharmaceutical compositions according to this invention are prepared in a suitable dosage form comprising an effective dose of at least one compound of formula (I) and at least a pharmaceutically acceptable inert ingredient.
Example of suitable dosage form are tablets, capsules, coated tablets, granules, solutions and syrups for oral administration, ointments and medical patches for topic administration; suppositories for rectal administration and sterile solutions for injectable, aerosolic and ophthalmic administration.
The dosage forms may also contain other conventional ingredients like: preservatives, stabilizers, surface-active agents, buffers, salts to regulate osmotic pressure, emulsifiers agents, sweeteners, colouring agents, flavouring agents and the like.
If required for particular therapies, the pharmaceutical composition of this invention may contain other active pharmacological ingredients where concomitant administration is therapeutically useful.
The amount of peptide of formula (I) in the pharmaceutical composition of this invention may vary in a wide range depending on known factors such as, for example, the type of disease to be treated, the disease severity, the patient weight, the dosage form, the route of administration chosen, the number of daily administrations and the efficacy of the selected peptide of formula (I).
Typically, the amount of peptide of formula (I) in the pharmaceutical composition of this invention will be such as to enssure an administration level of from 1 to 200 mg/Kg/day, preferably of from 2 to 50 mg/Kg/day.
The dosage forms of the pharmaceutical composition of this invention can be prepared according to techniques well known to the pharmaceutical chemist comprising mixing, granulation, compression, dissolution, sterilization and the like.